XML 134 R118.htm IDEA: XBRL DOCUMENT
v3.25.3

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Narrative (Details) - USD ($) $ in Thousands, shares in Millions |  |  | 12 Months Ended |
--- | --- | --- | --- | ---
Apr. 09, 2014 | Mar. 06, 2014 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 22, 2010
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |
Payment to redeem shares | $ 250,000 |  |  |  |  |
Parent Company |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |
Distribution received from subsidiary |  |  | $ 150,444 | $ 433,325 | $ 491,033 |
Common Stock |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |
Non-binding letter of intent to acquire common stock (in shares) |  | 40.3 |  |  |  |
Expense related to share redemption | $ 2,000 |  |  |  |  |
Atkore International | CD&R |  |  |  |  |  |
Condensed Financial Statements, Captions [Line Items] |  |  |  |  |  |
Preferred stock, percentage of outstanding capital stock (on an as-converted basis) (%) |  |  |  |  |  | 51.00%
Common stock, percentage of outstanding capital stock (%) |  |  |  |  |  | 49.00%

X
- Definition Payments For Repurchase Of Common Stock, Excluding Related Expense + References No definition available. + Details
Name: | atkr_PaymentsForRepurchaseOfCommonStockExcludingRelatedExpense
Namespace Prefix: | atkr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Payments For Repurchase Of Common Stock, Related Expense + References No definition available. + Details
Name: | atkr_PaymentsForRepurchaseOfCommonStockRelatedExpense
Namespace Prefix: | atkr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 04 -Paragraph a -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 5 -Subsection 04 -Paragraph c -Subparagraph Schedule I -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 7 -Subsection 05 -Paragraph c -Subparagraph Schedule II -Publisher SEC Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 9 -Subsection 06 -Publisher SEC Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 Reference 8: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481231/810-10-45-11 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 7 -Subparagraph (SAB Topic 1.B.2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480922/205-10-S99-7 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481003/205-10-S50-2 + Details
Name: | srt_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents disclosure of the aggregate cash dividends paid to the entity by consolidated subsidiaries. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-04(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3 + Details
Name: | us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_TreasuryStockSharesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_OwnershipAxis=atkr_AtkoreInternationalInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=atkr_ClaytonDubilierRiceLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |